Method onRender

src/ink/ink.tsx:420–789

()

    this.options.stdout.write('\x1b[?1004h' + (supportsExtendedKeys() ? DISABLE_KITTY_KEYBOARD + ENABLE_KITTY_KEYBOARD + ENABLE_MODIFY_OTHER_KEYS : ''));
  }
  onRender() {
    if (this.isUnmounted || this.isPaused) {
      return;
    }
    // Entering a render cancels any pending drain tick — this render will
    // handle the drain (and re-schedule below if needed). Prevents a
    // wheel-event-triggered render AND a drain-timer render both firing.
    if (this.drainTimer !== null) {
      clearTimeout(this.drainTimer);
      this.drainTimer = null;
    }

    // Flush deferred interaction-time update before rendering so we call
    // Date.now() at most once per frame instead of once per keypress.
    // Done before the render to avoid dirtying state that would trigger
    // an extra React re-render cycle.
    flushInteractionTime();
    const renderStart = performance.now();
    const terminalWidth = this.options.stdout.columns || 80;
    const terminalRows = this.options.stdout.rows || 24;
    const frame = this.renderer({
      frontFrame: this.frontFrame,
      backFrame: this.backFrame,
      isTTY: this.options.stdout.isTTY,
      terminalWidth,
      terminalRows,
      altScreen: this.altScreenActive,
      prevFrameContaminated: this.prevFrameContaminated
    });
    const rendererMs = performance.now() - renderStart;

    // Sticky/auto-follow scrolled the ScrollBox this frame. Translate the
    // selection by the same delta so the highlight stays anchored to the
    // TEXT (native terminal behavior — the selection walks up the screen
    // as content scrolls, eventually clipping at the top). frontFrame
    // still holds the PREVIOUS frame's screen (swap is at ~500 below), so
    // captureScrolledRows reads the rows that are about to scroll out
    // before they're overwritten — the text stays copyable until the
    // selection scrolls entirely off. During drag, focus tracks the mouse
    // (screen-local) so only anchor shifts — selection grows toward the
    // mouse as the anchor walks up. After release, both ends are text-
    // anchored and move as a block.
    const follow = consumeFollowScroll();
    if (follow && this.selection.anchor &&
    // Only translate if the selection is ON scrollbox content. Selections
    // in the footer/prompt/StickyPromptHeader are on static text — the
    // scroll doesn't move what's under them. Without this guard, a
    // footer selection would be shifted by -delta then clamped to
    // viewportBottom, teleporting it into the scrollbox. Mirror the
    // bounds check the deleted check() in ScrollKeybindingHandler had.
    this.selection.anchor.row >= follow.viewportTop && this.selection.anchor.row <= follow.viewportBottom) {
      const {
        delta,
        viewportTop,
        viewportBottom
      } = follow;
      // captureScrolledRows and shift* are a pair: capture grabs rows about
      // to scroll off, shift moves the selection endpoint so the same rows